Implantation bleeding or something else?

We're newly TTC and experienced a loss about 2 years ago. I was then was on BC up until the 14th of this month. I had the nexplanon implant and had to have it surgically removed (very annoying process). I've had cramps for about 2 days, some lower back pain and some digestive issues too. This morning after waking up with a VERY upset stomach, I had no bleeding. About an hour later I noticed some dark red blood, not a whole lot but (TMI) about 1.5 wipes worth? Had a very dark double opk on Thursday but also had a pretttttty close double line on the 19th as well. I know it's unlikely to have a BFP so soon, but should I test? AF should arrive around the 10th of September.